b, Murray et al. 1987, Feinsinger and Tiebout 1991,
Tiebout 1991, Podolsky 1992).
Hawkmoths (Sphingidae) Hawkmoths are crepus-
cular and nocturnal, hovering (even in strong winds;
Haber 1983a) to sip nectar through their long, unrolled
proboscises. Most hawkmoth-pollinated flowers pro-
duce copious nectar and strong sweet fragrances at
night (Haber and Frankie 1989, Proctor et al. 1996),
and deposit their pollen on the moth's proboscis,
head, or wings (Haber and Frankie 1983). In some taxa
(e.g., Epiphyllum sp,, Cactaceae), the flowers last
only one night. Many of Monteverde's hawkmoth-
pollinated plant species bloom during the wet sea-
son. In Monteverde, 91 plant species in 12 families
appear to be pollinated primarily by hawkmoths (ca.
4% of the flora; Table 8.1). The majority belong to the
plant families Rubiaceae, Bromeliaceae, and Fabaceae,
and most are trees or epiphytes.
The pollination systems of some of Monteverde's
hawkmoth-pollinated plant species have been diffi-
cult to infer from their floral traits. Certain Inga spp.
(Fabaceae) trees, for example, which are pollinated by
hawkmoths, appear to be adapted for bird or bat pol-
lination because they lack the potent fragrances gen-
erally considered to be characteristic of hawkmoth
flowers (Koptur 1983; see Koptur, "Breeding Sys-
tems of Monteverde Inga," pp. 85—87). The tree genus
Quararibea (Bombacaceae) is also pollinated by hawk-
moths despite exhibiting characteristics of both moth-
and bat-pollination systems and despite visitation by
birds and a wide variety of diurnal and nocturnal
insects (W. Haber, pers. comm.).
The larvae and adult hawkmoth fauna (88 species;
W. Haber, pers. comm.) and plants adapted for hawk-
moth pollination of Monteverde have been identified.
(Haber and Frankie 1989, W. Haber, unpubl. data,
S. Kinsman, W. Haber, and C. Mulder, unpubl. data)
Studies of the moths' foraging behavior and foraging
ranges (Haber and Frankie 1989) would be helpful to
understand their plants' mating structure and the role
of increasing forest fragmentation in the persistence of
both partners of the mutualism. The increase in street-
lights and advertising lights of the Monteverde commu-
nity may affect hawkmoths' foraging and populations.
Smaller fliers: insects. Small moths Small moths,
most of them nocturnal, are more likely to settle on
flowers than to hover. The pale tubular flowers they
visit tend to open and produce sweet scents and nec-
tar through the night, starting at dusk. In the Monte-
verde flora, adaptation specifically for pollination by
small moths is evident in 89 species (ca. 4% of the
flora; Table 8.1); nearly half of these species are trees.
Plant families richest in moth-pollinated species are
the Rubiaceae, Fabaceae, and Meliaceae.
Butterflies Butterflies also settle on flowers to
suck nectar but are diurnal. The flowers they visit pro-
duce abundant nectar and are colorful, sweet scented,
and tubular (or spurred) with a rim. In Monteverde,
relatively few plant species (48) are adapted specifi-
cally for pollination by butterflies. Possible mimicry
for pollination in some species has been studied else-
where (Endress 1994). One plant family (Asteraceae)
accounts for the majority of butterfly-pollinated
plants, which are predominantly herbs, shrubs, and
epiphytes. Although butterfly mobility and migration
have been documented (Haber 1993), little is known
about butterfly pollination in neotropical forests
(Bawa 1990). Monteverde's butterflies are easily iden-
tified (DeVries 1987), and the butterfly-pollinated
shrubs in Monteverde are accessible for research. The
within- and between-plant patterns of pollen move-
ment associated with pollinator behavior and floral
density and phenology are of particular interest.
Beetles Colors, scents, and shapes of flowers pol-
linated by beetles vary considerably, and pollinating
beetles vary substantially in size, morphology, and
behavior. Most beetles clamber over flowers as they
feed on pollen, and in many beetle-pollinated plants
the flowers are open, flat, and produce abundant pol-
len. Other beetle-pollinated plants have specialized
arrangements of flowers (see Goldwasser, "Scarab
Beetles," pp. 269-271). In Monteverde, as in other
neotropical forests, certain monocot families (e.g.,
Araceae and Cyclanthaceae) account for most of the
69 beetle-pollinated species. Herbs, vines, and epi-
phytes are common among beetle-pollinated plants.
Many (62% of species) have separate male and female
flowers.
Beetle pollination has received little attention but
is now considered important in tropical communities
(Schatz 1990, Young 1990) and critical for under-
standing and managing tropical forests (Irvine and
Armstrong 1990). One remarkable interaction occurs
between scarab beetles and heat-producing flowers
in Monteverde (see Goldwasser, "Scarab Beetles,"
pp. 269-271). Study of the Araceae and Cyclantha-
ceae in Monteverde could substantially contribute to
understanding roles of beetle pollination in tropical
montane forests.
Flies Flies are not common pollinators. Fly-
pollinated flowers vary in color, odor, and timing of
opening, and the nectar tends to be exposed to for-
agers of diverse morphology and behavior (Proctor
et al. 1996). Flowers that appear to be adapted pri-
marily for pollination by flies are not well studied
(Bawa 1990) and are infrequent in Monteverde (Table
8.1). The five species in Monteverde are herbs, shrubs,
or small trees in the Acanthaceae, Aristolochiaceae,
and Rubiaceae.248 Plant-Animal Interactions